In current pre-portioned systems for preparing beverages, such as for example systems for extracting espresso coffee starting from disposable cartridges, the substances from which the beverage is to be extracted are contained in hermetic cartridges made mainly of injection-molded or thermoformed plastic material or of metallic material such as aluminum.
It is known that these cartridges must be pierced at the bottom when the beverage is extracted, in order to allow the outflow thereof toward the outside, and typically the solutions for performing this piercing process are various. External piercing elements arranged on the machine are known, for example from European Patent Application EP1674007, or solutions that utilize the internal hydraulic pressure of the cartridge to create an outflow path for the beverage are known and described for example in European Patent Applications EP1555218 and EP2177460 or in PCT Application WO02/081337.
Other solutions instead do not provide for opening the cartridge at the time of use, but the cartridge is provided, already at the outset, with openings for the passage of the extracted beverage toward the outside. The latter solutions are not free from drawbacks, among which the fact must be noted that these known cartridges, obtained typically by injection molding, do not ensure such protection to the substance that they contain as to allow its preservation for a period suitable for the distribution and consumption cycles of the product. Further external packaging with barrier properties against external agents, such as for example humidity and oxygen, is therefore required in order to ensure the long-term preservation of the substance.
Moreover, the production of these cartridges requires the use of an excessive amount of plastic that consequently has a high environmental impact. Moreover, the particular stiffness of the cartridge does not allow separation between the plastic and the substance contained therein for sorted waste disposal.
A solution is known from European Patent EP1580144B1 in which the hermetically closed cartridge is obtained by sealing thermoformed components and contains inside it a fixed piercing element, which is activated by mechanical interference with the extraction chamber at the time of loading of the cartridge in the dispensing system and allows conveying the beverage directly into the cup, since no obstacles are interposed between the opening created by the internal piercing element, the extraction chamber and the cup.
This known cartridge solves part of the drawbacks of the background art, such as for example the high environmental impact, but has in some cases a less than optimum conveyance of the beverage and, in the particular case in which the beverage to be obtained is espresso coffee, does not make it possible to obtain a layer of crema that is abundant and persistent over time.